Messages in this thread Patch in this message | | | From | Mathieu Desnoyers <> | Subject | [RFC PATCH v2 2/3] thread_local_abi: wire up x86 32/64 system call | Date | Tue, 22 Dec 2015 13:02:12 -0500 |
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Wire up the thread local ABI on x86 32/64. Call the thread_local_abi_handle_notify_resume() function on return to userspace if TIF_NOTIFY_RESUME thread flag is set.
This provides an ABI improving the speed of a getcpu operation on x86 by removing the need to perform a function call, "lsl" instruction, or system call on the fast path.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> CC: Russell King <linux@arm.linux.org.uk> CC: Catalin Marinas <catalin.marinas@arm.com> CC: Will Deacon <will.deacon@arm.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Paul Turner <pjt@google.com> CC: Andrew Hunter <ahh@google.com> CC: Peter Zijlstra <peterz@infradead.org> CC: Andy Lutomirski <luto@amacapital.net> CC: Andi Kleen <andi@firstfloor.org> CC: Dave Watson <davejwatson@fb.com> CC: Chris Lameter <cl@linux.com> CC: Ingo Molnar <mingo@redhat.com> CC: Ben Maurer <bmaurer@fb.com> CC: Steven Rostedt <rostedt@goodmis.org> CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> CC: Josh Triplett <josh@joshtriplett.org> CC: Linus Torvalds <torvalds@linux-foundation.org> CC: Andrew Morton <akpm@linux-foundation.org> CC: Thomas Gleixner <tglx@linutronix.de> CC: linux-api@vger.kernel.org --- arch/x86/entry/common.c | 2 ++ arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + 3 files changed, 4 insertions(+)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index a89fdbc..222cacf 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -249,6 +249,8 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags) if (cached_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); + if (thread_local_abi_active(current)) + thread_local_abi_handle_notify_resume(current); } if (cached_flags & _TIF_USER_RETURN_NOTIFY) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index f17705e..c6c385e 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -383,3 +383,4 @@ 374 i386 userfaultfd sys_userfaultfd 375 i386 membarrier sys_membarrier 376 i386 mlock2 sys_mlock2 +377 i386 thread_local_abi sys_thread_local_abi diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 314a90b..748aee3 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -332,6 +332,7 @@ 323 common userfaultfd sys_userfaultfd 324 common membarrier sys_membarrier 325 common mlock2 sys_mlock2 +326 common thread_local_abi sys_thread_local_abi # # x32-specific system call numbers start at 512 to avoid cache impact -- 2.1.4
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